In a conventional magnetic shield room, as shown in Patent Document 1 below, an inner space is surrounded by an upper member (may also be referred to as “ceiling member”), a side peripheral member (may also be referred to as “wall member”) and a lower member (may also be referred to as “floor member”) all of which are made of a material having high magnetic permeability, and the above inner space is shielded from an external environmental magnetic field to crease a low magnetic field therein. The magnetic shield room is also used for the measurement of a magnetocardiogram (Patent Document 2 below)